gdb: Convert language la_print_typedef field to a method

This commit changes the language_data::la_print_typedef function
pointer member variable into a member function of language_defn.

There should be no user visible changes after this commit.

gdb/ChangeLog:

	* ada-lang.c (ada_language_data): Delete la_print_typedef
	initializer.
	(ada_language::print_typedef): New member function.
	* c-lang.c (c_language_data): Delete la_print_typedef initializer.
	(cplus_language_data): Likewise.
	(asm_language_data): Likewise.
	(minimal_language_data): Likewise.
	* d-lang.c (d_language_data): Likewise.
	* f-lang.c (f_language_data): Likewise.
	(f_language::print_typedef): New member function.
	* go-lang.c (go_language_data): Delete la_print_typedef
	initializer.
	* language.c (language_defn::print_typedef): Define member
	function.
	(unknown_language_data): Delete la_print_typedef initializer.
	(unknown_language::print_typedef): New member function.
	(auto_language_data): Delete la_print_typedef initializer.
	(auto_language::print_typedef): New member function.
	* language.h (language_data): Delete la_print_typedef field.
	(language_defn::print_typedef): Declare new member function.
	(LA_PRINT_TYPEDEF): Update call to print_typedef.
	(default_print_typedef): Delete declaration.
	* m2-lang.c (m2_language_data): Delete la_print_typedef
	initializer.
	(m2_language::print_typedef): New member function.
	* objc-lang.c (objc_language_data): Delete la_print_typedef
	initializer.
	* opencl-lang.c (opencl_language_data): Likewise.
	* p-lang.c (pascal_language_data): Likewise.
	(pascal_language::print_typedef): New member function.
	* rust-lang.c (rust_print_typedef): Delete function,
	implementation moved to rust_language::print_typedef.
	(rust_language): Delete la_print_typedef initializer.
	(rust_language::print_typedef): New member function,
	implementation from rust_print_typedef.
	* typeprint.c (default_print_typedef): Delete.